Kinetics of Drug Degradation and the Effect of pH on Drug Stability Lab Report

Kinetics of Drug Degradation and the Effect of pH on Drug Stability - Lab Report Example This iodine level reading then indicates the amount of iodine and therefore the amount of the drug that had been degraded and subject to the reaction with the used up iodine (Yoshioka and Stella 2000, pp. 61-69; Cohen et al. 1984; Brucat n.d.; Laude 2011; Stretton 2004). The spectrophotometer was calibrated to 324 nm for wavelength, zeroed with the use of water, and set to absorbance recording. For the trial run, 250 mL capacity Flask 2 was used to hold 10 mL of the drug in aqueous solution making use of a pipette, together with 120 mL of water. 250 mL capacity Flask 1 was used to hold 10 mL of water, 50 mL of aqueous iodine solution, and 10 mL of H2SO4, 0.1 M, likewise making use of a pipette. All of Flask 1 was poured into Flask 2, and swirled, at the same time marking the start of the timer. Flask 2 contents were poured back into Flask 1. At the 30 second mark, the reading for absorbance is noted, and this reading is done for every 30 seconds up to the six minutes mark. The pH of the mixture is also noted. This is a run. The actual experiment is done in five iterations of this run, with the initial Flask 2 contents retained, while the Flask 1 acid and water levels were varied according to the table below (Yoshioka and Stella 2000, pp. 61-69; Cohe n et al. 1984; Brucat n.d.; Laude 2011; Stretton 2004): Using the data for the absorbance at different pH and time, the gradient is calculated with the use of LINEST and SLOPE to determine the rate of reaction. Both yield the same results. The derived rates of reaction are given below: The rate of decline of iodine concentrations is a function of the acidity of the solution, as can be seen in Graph 1. Where the pH is most acidic, which is experiment 5 at a pH value of 2.05, the rate of decline is fastest. This corresponds to the fastest rate of degradation for Drug X. Graph 2 is to be interpreted in the same manner. Where the slope is least negative